Who Is He? The young chairman of the House Budget Committee came to national prominence as architect of a Republican budget plan after the GOP took the House in the 2010 midterm elections. Ryan's plan would slash government spending, simplify tax laws while cutting taxes on the wealthy, and fundamentally change entitlement programs, including Medicare and Medicaid. The seven-term congressman representing southeastern Wisconsin's1st Congressional District has been a member of Congress since age 28.

Age: 42, born in Janesville, Wis.

Experience: House member since 1999 and Budget Committee chairman since 2011. Also serves on tax-writing Ways and Means Committee. Before entering Congress, worked on the 1996 vice presidential campaign of Jack Kemp, for Sen. Sam Brownback of Kansas and for Sen. Robert Kasten of Wisconsin.

Legislative Highlights: Ryan's budget plans have passed the GOP-controlled House but not the Democratic-controlled Senate. Supported President Obama's auto bailout, which is often derided by Mitt Romney. He turned down an offer to become President George W. Bush's budget director during Bush's second term.

How He Helps Romney: Ryan delights cultural and fiscal conservatives (The Wall Street Journal, Weekly Standard and National Review all had urged the pick in recent days). He instantly helps to energize the party's base: Former Pennsylvania Sen. Rick Santorum, who attracted conservatives in the GOP primary, lauded the choice of a " full-spectrum conservative" who is "solidly pro-life, pro-family." He could help Romney in the battleground state of Wisconsin and perhaps elsewhere in the Midwest.

What Democrats Are Saying: Thechoice only magnifies Obama's claims that Romney's policies would help the rich at the expense of middle-class Americans. In a statement, the Obama campaign said Romney's choice of "the architect of the radical Republican House budget" gives him a running mate "who shares his commitment to the flawed theory that new budget-busting tax cuts for the wealthy, while placing greater burdens on the middle class and seniors, will somehow deliver a stronger economy."

Family/Personal: Maintains a home in Janesville, Wis., with wife, Janna, and three young children: daughter, Liza, and sons Charlie and Sam. The fifth-generation Wisconsin native has personal assets somewhere between $927,100 and $3.2 million, according to financial disclosure forms, as reported by Politico.

Religion: Catholic

Education: Bachelor's degrees in economics and political science from Miami University in Ohio.

Fun Facts:

Ryan has worked as a personal trainer at a gym and as a waiter at the Capitol Hill Mexican restaurant Tortilla Coast, The New York Times reports.

Quote: "They come up on your hand, and you just squeeze wherever you are in that fish and pull it out. ... I know it sounds a little crazy, but it's really exhilarating." – Ryan, on the appeal of catching catfish by hand, another hobby.